Engine starter



June 24, 1947. Q ET L I I 2,423,068

anemnsmmna Filed Aug. 2, 1945 2 Sheets-Sheet 2 Y wwww WITNESS 1 QWZCMZ'zZ/n x in which the detent Patented June 24, .1947

' Edwin Elliott Hoo James E. Buxton,

Christi an, Y.', assignors to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application Augusta-194s, Serial No. 608,514 I 6Claims. (01314-7) The present invention relates to an engine starter drive and more partlcularlyto thattype of starter in which a connected to a gear until the operator'causesthe starting mechanism to be deenergized. Starting drives of this type, such as exemplified in the patent to Buxton,

2,332,986, usually incorporate means such as a detent for holding the pinion in mesh with the engine gear, and a clutch between the pinion and the member from which it is driven to permit overrunning of the pinion when the engine starts.

It is an object of the present invention to provide a novel starter of the above type incorporating a detent of simple and economical conpinion remains operatively on the engine to be started struction in association with the starter drivefor assisting the engagement of the pinion with the engine member and ation. I j t It, is a further object to provide such a device continuing such engagement until the operator interrupts the starting operhaving a detent under the control of the operator for cooperating with a pinion driving member to assist movement of the pinion into mesh with the engine gear and thereafter oppose demeshing until the operator releases thestarting switch.

It is a further object to provide such a device having a detent so th starting drive as. to bear on a pinion driving sleeve whilethe with the engine gear, but is free of the driving sleeve when full mesh of thepinion is secured.

It is another object to provide "such a device in whichthe detent with its operating means is combined with tive unit.

It is a further object to provide such adevice with a friction block for contacting a member attached to the pinion and preventing wear on the flexible detent.

Further objects and advantages will be ap parent to those skilled in the art from theiollowing description in connection with the acco m panying drawing, in which: Fig. l is a side elevation,

in idle position;

Fig; 2 is a view similar to Fig. 1 with the parts thereof in the positions assumed when the engine the starting switch as an operais flexible to permit the pinion to demesh if heavilystressedby unusual condisuch a device in whichthe flexible detent is further provided a positioned with reference to pinionis traversing into mesh 30 -type, having one toothed of the pinion; and 1 member in the form of starts and the pinion overruns the starting motor;

Fig. 3 is a viewsimilar to Fig. 2 illustrating a second embodiment of the invention wherein the flexible detent isin operation during overrunning Fig. 4 is a viewsimilar to Fig. 3 showing a third embodiment of the invention in which the flexible a friction block bearing one memberattached to the pinion during overa detent is provided with running of the pinion.

In Fig. 1, of the drawingthereis shown a por- SM having an armature tion ofa starting motor shaft I provided witha smooth reduced extension 2. A sleeve 3 having a portion 4. of enlarged diameter is secured onrthe outer end of theshaft I asby means of an apinion 6 is journalled on the reducedfportion 2 to be traversed into and out of engagement with an engine member in Means for actuating the pinion 6 is provided,

comprising an operating member in the form of t a screw shaft 8, threaded at 9, slidably journalled on the sleeve 3 and yieldably driven'therefromas by means of a drive spring ll, anchored at its ends to said sleeve and shaft respectively. A control member for the pinion sion of said control member. therear'portion of,

which is of reduced diameter as indicated at, creating an inclined step or shoulder, l5. Disconnectable driving means are provided between the nut i2 and pinion 6 in the form of anoverrunning clutch, indicated generally by numeral i6. As here shown, this clutch is of the dental i9 'journalled on the pinion hub and keyed to the barrel i3 as by means of lugs 2| on the plate posed between the plates, the separation of the plates being limited by. an abutment ring 23 locked in place 9. partly in section, of t a preferred form of the invention with the parts has of the pinion 6 0n the shaft I into mesh with the engine gear when the motor is energized, and to oppose premature demesh of the pinion. To this anchor pin 5. A driving H of the shaft in position the form of a. ring gear 1.

is provided in the form or a nut l2 threaded on the operating mem plate I] non-rotatably mounted on the hub of the pinionat i8, anda (mating toothed plate 22. Means are provided for t end, means for restraining initial rotation of the pinion is provided in the form of a detent 26 which is located close to the pinion driving barrel and is movable into frictional engagement therewith. The detent is preferably controlled by the operator as an incident to the energiza tion of the starting system. As shown, this is 3|. The switch 28 can be of any desired conven tional construction and is energized from a battery 32 through a manual switch 33, the coil 36 of the switch being grounded at 34. Closure of the starting switch is arranged to connect the starting motor SM to the battery 32, the battery and'starti'ng motor being grounded at 31 and 38 respectively to complete the starting circuit.

In order to perform its second function of bolding the pinion in mesh with the engine gear until a true start is secured, the detent 26 is so located that the final meshing movement of the pinion causes the detentto run on the shoulder l5; and the portion l4 of barrel I3 is sufliciently reduced in diameter to clear the detent and thereby permit rotation-of the barrel without retardation by the detent as illustrated in Fig. 2. Under these circumstances, any attempt of the barrel to demesh the .pinion, while the starting switch is closed. will be opposed by engagement of the detent against the shoulder H. border that the pinion may overrun freely when the engine starts, the detent is so located with respect to the shoulder I! as to permit the barrel to move back sufflciently to allow disengagement of the overrunthus causing the starting switch 28 to open and deenergize the starting motor, and at the same time moving the detent 26 out of engagement with the barrel l3. The rotation of the engine gear 1 causes the pinion to rotate faster than the starting motor, and the pinion is accordingly traversed backward into demeshed position by virtue of the torque transmitted from the pinion to the control nut by the frictional driving contact of the ends of spring 25 within the clutch l6.

Should the initial explosions of the engine be weak, the operator will keep the manual switch I 33 closed, thus maintaining the detent 26 in operative position to oppose demesh of the pinion 6 by contact of the shoulder IS on the detent. Since the main driving force tending to demesh the pinion while the clutch plates I9 and H are separated is transmitted frictionally through the ning clutch l6 before the'detent engages said shoulder.

Fig. 2 of the drawing shows the starting drive in overrunning position with the. detent {26 contacting against the stop shoulder II to prevent disengagement of the pinion 6 from the engine gear 1 and with the clutch parts I! and I3 separated.

In operation; the'operator presses the push button 33, thus completing a circuit through the battery 32, through push button 33, solenoid coil spring 25 within the clutch l6, only a light pressure. of the detent 26 is necessary to efi'ectively overcome the demeshing efiort. When the force of the explosions is expended therefore, the cranking operation is immediately resumed and continued until a successful start has been secured.

its free end. 7

In idle position, the hook 43 of the detent 4| is positioned so as to clear the barrel I3 but upon actuation of the starting solenoid 28 by means of the manual switch 33, the plunger 21' presses against the detent 4| to flex it into frictional contact with the barrel. Simultaneously the motor shaft I is rotated and the pinion 6 is thereby traversed into mesh with the engine gear to crank the engine, the detent meanwhile restraining ro- 36, and groundconnection 34' to energize the,

main starting switch 26. Upon closure of the starting switch, another circuit is established from the battery 32 through the starting switch to the starting motorSM and ground connection 33 to energize the starting motor and rotate the motor shaft I. At the moment that the motor shaft starts to rotate, the detent 26 has already contacted the barrel |3 due to the energization of solenoid 36, so as to frictionally prevent rotation of the nut member l2, and since the screw shaft 3 is rotating, the nut member and barrel will be traversed toward the starting motor. The consequent thrust transmitted from the barrel through the clutch members I9, 25 and I1 traverses the pinion 6 toward the shoulder 39 formed by the reduction in diameter of shaft When the sliding motion of the pinion is arrested by the shoulder 39 incident to full mesh of the pinion 6 with the engine gear I, the clutch parts l9 and H come into firm engagement so as to transmit torque from the motor shaft to the pinion 6. When the engine is successfully started, the operator releases the control'switch 33,

tation of the barrel l3 to assist such traversal. In a normal tarting operation, the manual switch 33 is 0 ed as soon as the engine becomes selfeoperative nd the consequent deenergization of the solen d 36 releases the detent 4| and thereby permits the pinion andits associated parts to move back to idle position; If an abnormally great demeshing force is encountered due to excessive drag of the overrunning clutch l6 or otherwise, the barrel I3 will flex the spring I 28 is closed, the solenoid plunger 21' presses the block 44, into firm contact with the barrel |3' thus affording sufiicient frictional drag to overcome the tendencyof the pinion to/ emesh. Howeven if the demeshing force be mes unusually great due to a fouled clutch or otherwise, the detent hook 43 will be flexed outward by the barrel l3 permitting the pinion to demesh the same as in the previous embodiment of the invention.

It will be seen that there is here provided a starting system incorporating a drive pinion which is moved automatically into engagement with member of an engine to. be started, and motor including a pinion slidably iournalied on a manually controlled detent formed as a part said shaft for traversal into mesh with a gear of a magnetic starting switch unit, for assisting. on the engine to be started, means for actuating the meshing of the pinion and for holding the said pinion including a screw shaft fixed to said pinion in mesh during false starts and until remotor shaft, a barrel, a control nut therein leased bythe operator. 1 threaded on the screw shaft, and an overrunning Although certain embodiments of the invenclutch connecting the barrel to the pinion closed tion have been shown and described in detail, it by the final movement of the control nut, and will be understood that other embodiments are means under the control of said manual switch possible, and the form and arrangement of the for insuring meshing and opposing demeshing of parts may be changed without departing from the pinion, including an elongated spring prothe spirit of the invention. vided with a contact block for frictionaliy engag- What is claimed is: ing said barrel and with a hooked end arranged 1. In an engine starter, a motor shaft, 9. pinto yieldably limit the demeshing movement of ion journalled thereon for traversal into and out the barrel.

of mesh with a gear on the engine to be started, 5. In an engine starter, a motor shaft, 2. pinmeans including an operating member driven ion slidably iournalled on said shaft for travfrom the motor shaft for actuating said pinion, ersal into mesh with a gear on the engine to be said means further including a control member started, a screw shaft drivingly connected to and a barrel forming an extension thereof havthe motor s aft, means for actuating the pinion ing with said shoulder for opposing demeshing of the control nut; and a starting switch comof the pinion. prising a movable plunger extending from the 2. In an engine starter drive, a motor shaft, 1 switch toward the periphery of the sleeve, and a screw shaft mounted on the motor shaft and a detent carried by the plunger adjacent the connected to rotate therewith, a pinion joursleeve, movable by closure of the starting switch nailed on the motor shaft for movement into and into frictional engagement with the sleeve. out of engagement with a gear of th engine to 6. In an engine starter, a motor shaft, a screw be started, a control nut having an extended shaft drivingly connected thereto; a pinion havsleeve threaded on the screw shaft, means ining an extended hub slidably joumalled on the eluding a clutch for connecting the control nut motor shaft for movement into mesh with a gear to the pinion and means for insuring meshing on the engine to be started, a control nut threadand preventing demeshing of the pinion included on the screw shaft for controlling movements ing a detent movable into and out of frictional of the pinion, having an elongated sleeve fixed into contact with the sleeve and simultaneously 4 cl tch mounted on the hub of said pinion conenergizing the starter, necting the control nut and pinion; and means 3. In an engine starter, a motor shaft a pinunder the control of the operator including a ion slidably journalled on said shaft for travyieldable detent for cooperation with said shoularea! into mesh with a gear on the engine to be der to prevent premature demesh of the pinion.

started, means for actuating said pinion includ- E. ELLIOTT HOOD.

ing a screw shaft fixed to said motor shaft, a FRANK T. CHRISTIAN.

control nut threaded on the screwshaft, a sleeve AMES E. B XTON- attached to said nut. and a clutch between the sleeve and pinion closed by the final movement 1 REFERENCES CITED of the control nut; and means for insuring mesh The following references are of, record in the ing and preventing demeshing of the pinion 111-, file of this patent: eluding a. flat spring, having an inclined tip, and

a solenoid plunger fo moving said spring into UNITED STATES PATENTS frictional engagement with the sleeve. Number 0 Name Date 4. In an engine starting mechanism, a start- 2,339,486 Kearney Jan. 18, 1944 ing circuit, a motor and a manual switch in said 2,394,690 Hood Feb. 12, 1946 starting circuit, a starting drive actuated by said 2,397,033 Miller Mar. 19, 1946 

